Shutoff device for hollow electrodes

ABSTRACT

Shutoff device for hollow electrodes supplying particulate feed material to and/or supplying gas to or removing furnace gas from electrothermal reduction furnaces, arc melting furnaces, for example calcium carbide furnaces. A supply means mounted on the hollow electrode is formed with a thrust rod slidable therein, coaxially with respect to the electrode, and a stopper is detachably secured to the thrust rod which can be actuated from the outside and enables the stopper to be moved inside the supply means from a position permitting the free supply and removal of material through the electrode to a position inside the electrode where the supply and removal of material therethrough is arrested, and inversely. The shutoff device is more particularly formed with a solid stopper having at least one corrugated steel compensator associated to it for sealing the gap left between the stopper and electrode inside wall.

United States Patent Fritz Muller Knapsack near Cologne;

Hugo Werner, Hermulheim near Cologne; Werner Nolden, Bruhl, all of, Germany Inventors Knapsack bei Cologne, Germany Apr. 17, 1969 Germany Priority SHUTOFF DEVICE FOR HOLLOW ELECTRODES 12 Claims, 3 Drawing Figs.

U.S. Cl 13/18 Int. Cl 1105b 7/06 Field of Search 13/9, 18,33

References Cited UNITED STATES PATENTS 3,370,1l9 2/1968 Grimm et al 13/9 X 3;47k,626- 10/1969 Weese etal Primary'Examiner-Bernard A. Gilheany Assistant ExaminerR. N. Envall, Jr. An0rneyConnolly & Hutz ABSTRACT: Shutoff device for hollow electrodes supplying particulate feed material to and/or supplying gas to or removing furnace gas from electrothermal reduction fumac'es,-arc melting furnaces, for example calcium carbide furnaces. A supply means mounted on the hollow electrode is formed with a thrust rod slidable therein, coaxially with respect to the electrode, and a stopper is detachably secured to the thrust rod which can be actuated from the outside and enables the stopper to be moved inside the supply means from a position permitting the free supply and removal of material through the electrode to a position inside the electrode where the supply and removal of material therethrough is arrested, and inversely. The shutoff device is more particularly formed with a solid stopper having at leastone corrugated steel compensator associated to it for sealing the gap left between the stopper and electrode inside wall.

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' SIIUTOFF DEVICE FOR HOLLOW ELECTRODES plying gas to or removing furnace gas from electrothermal reduction furnaces; arc melting furnaces, for example calcium carbide furnaces, phosphorus furnaces or similar furnaces, wherein a supply means mounted on the hollow electrode is formed with a thrust rod slidable therein, coaxially with respect to the electrode, and wherein a stopper is detachably secured to the thrust rod which can be actuated from the outside and enables the stopper to be moved inside the supply means from a position permitting the free supply and removal of material through the electrode to a position inside the electrode where the supply and removal of material therethrough is arrested, and inversely.

Shutoff devices of the type described above are normally fitted with a stopper variable in diameter. The materials used for making the stopper are often found to be either sensitive to heat, especially at elevated temperatures, or to have poor mechanical strength. As a result, the stoppers are not always suitable for packing or sealing hollow electrodes, especially in those cases in which a defective stopper must be expected to entail the outbreak of toxic gas evolved inside the furnace, through the hollow electrode. This is the case, for example, with all hollow electrode-fitted furnaces inside which an atmosphere containing considerable carbon monoxide prevails. This is certainly and more importantly the case with phosphorus furnaces, where the possible outbreak firstly of carbon monoxide and secondly of phosphorus in vapor from entail heavy risks that cannot be excluded with certainty. Hazardous is more especially the presence of phosphorus-containing gases which may effect the elastic packing material andsealing areas with the result that the shutoff means then naturallyceases to be satisfactorily sealed.

The object of the present invention is to provide a shutoff means for hollow electrodes supplying particulate feed material to and/or supplying gas to or removing furnace gas from electrothermal furnaces, such as those described hereinabove, which is free from the deficiencies reported and designed so as to enable the hollow electrode to be reliably sealed, even in those cases in which conventional stoppers cease to function. This is substantially achieved in accordance with the present invention through the use of a stopper made of solid material end of at least one corrugated steel compensator to seal the gap left between the stopper and electrode inside wall, the compensator being positioned so as to bridge the said gap. To this effect, it is possible for the corrugated steel compensator to be secured to the electrode inside wall. Metals, ceramic materials, glass or similar material should conveniently be used for making the stopper which conveniently comprises a cylindrical middle portion and two conically tapered, preferably slightly conical, end portions. While steel and steel alloys are the metals which are preferred for making the stopper, it is also possible and advantageous to use nonferrous metals'and alloys thereof.

The shutoff device so designed has been found to perfectly satisfy the requirements of the present invention. In other words, corrugated steel is substituted for the elastic material formerly used for making the sealing element variable in diameter. As a result, the sealing element is a corrugated steel compensator which combines unsusceptibility to heat with the elastic mechanical strength necessary to reliably seal the hollow electrode.

A further feature of the present invention provides for the individual tubular electrode sections forming the electrode inside tube to be arranged so as to be spaced from one another and screwed together by means of a sleeve, the corrugated steel compensator being positioned in the gap left between the individual tubular electrode sections, and arranged so as to bear against a spacer shoulder formed on the sleeve, or secured thereto in different manner.

Another feature of the present invention provides for the thrust rod and the stopper to be connected together or disconnected by means ofa bayonetjoint.

Still another feature of the present invention provides for the thrust rod to be guided in gastight fashion by means of a packing box secured to the top of a headpiece.

In accordance with a further feature of the present invention the stopper comprises three parts and clampingly receives at least one corrugated steel compensator.

The top portion of the stopper is preferably formed with a bore receiving the threaded pin of the stopper base portion, through an interposed intermediary clamp collar.

A further feature of the present invention provides for a corrugated steel compensator to be clampingly positioned between the stopper head portion and the intermediary clamp collar and/or between the stopper base portion and the intermediary clamp collar.

A still further feature of the present invention provides for the corrugated steel compensator to be positioned so as to bear against a shoulder formed on the stoppers head or base portion.

In accordance with yet another feature of the present invention, the stopper base portion has bores receiving a screw spanner for screwing the threaded pin thereinto.

An exemplary embodiment of the present invention is shown diagrammatically in the accompanying drawings. Needless to say the invention is not limited thereto and admits of various variations and modifications without departing from its scope. Referring to the drawings:

FIG. 1 is a side elevational view of the shutoff means, partly in section;

FIG. 2 is a representation on an enlarged scale of part A shown in FIG. 1; and

FIG. 3 is a representation of the embodiment shown in FIG. 2, slightly modified.

The shutoff device of the present invention shown diagrammatically in the accompanying drawings is used in connection with hollow electrodes 10 supplying particulate feed material to and/or supplying gas to or removing furnace gas from electrothermal reduction furnaces, are melting furnaces, e.g. calcium carbide furnaces, phosphorus furnaces or similar furnaces. The shutoff device substantially comprises a headpiece 11 receiving thrust rod 12 which is slidable therein, coaxially with respect to electrode 10. Thrust rod 12 has a stopper I3, 13, 13" detachably secured to it and enables the stopper to be moved inside headpiece 11 from a position permitting the free supply and removal of material through the electrode to a position inside electrode 10, in which the electrode passageway 14 is closed, and inversely, by actuating thrust rod 12 from the outside. Stopper I3, I3, 13 is a solid material stopper. The gap left between stopper 13, 13, I3" and the electrode inside wall or tube 15 is sealed by means of at least one corrugated steel compensator 16 which is arranged so as to bridge the said gap left between electrode inside wall or tube 15 and the said stopper l3, l3, 13'.

As shown in FIG. 2, corrugated steel compensator I6 is secured to electrode inside wall 15. In the exemplary embodiment shown in FIG. 2, stopper I3, l3, 13" is a steel stopper having a cylindrical middle portion 13, a conically tapered head portion 13' and a conically tapered base portion 13'', which preferably have a slightly conical shape. The steel stopper 13, 13,13" can be replaced by a stopper made'up of a steel alloy having the necessary thermal and mechanicalproperties, or nonferrous metals and alloys thereof, or further materials having the necessary thermal and mechanical strength, for example ceramics, if desired or convenient.

The individual tubular electrode sections 15 'fonning the electrode inside wall or tube I5, 15" are arranged soas to be spaced from one another and screwed together by means of sleeve 17, which is a threaded sleeve whose individual threads coact mechanically with thread 18 and thread I9 in tubular electrode sections 15' and 15''. Corrugated steel compensator 16, which is arranged so as to bear against a spacer shoulder 21 formed on sleeve 17 is positioned in gap 20 left between the individual tubular electrode sections and 15". Thrust rod 12 and stopper 13, 13', 13" can be connected together and disconnected by means of a bayonet joint (not shown in the drawing). A packingbox 22 fast with top portion 30 of headpiece 11 enables thrust rod 12 to be passed therethrough in gastight fashion.

In the exemplary embodiment shown in FIG. 3, the shutoff means has a stopper 13 comprising three parts and at least one corrugated steel compensator 31 or 32 which is clamped thereto. The stopper head portion is formed with a bore receiving the threaded pin 34 of the stopper base portion 13", through an interposed intermediary clamp collar. A corrugated steel compensator 31, 32 is arranged so as to be clampingly held between the stopper head portion 13' and intermediary clamp collar 33 and/or between the stopper base portion 13" and intermediary clamp collar 33. The steel compensator bears against a shoulder formed on the stopper head portion 13' or base portion 13". This latter part 13" has bores receiving a screw spanner for screwing threaded pin 34 into bore 35.

The shutoff device of the present invention is handled in the following manner. During normal operation, the mixture of flux and ores travels through screw conveyor 23, downpipe 24 (during this phase pipe 24 is flanged to slide 27 by means of flange 25 and flange 26) open slide 27 and electrode passageway 15 to the furnace. During this normal phase of operation, stopper 13, 13, 13" does not occupy the position (unbroken lines) inside electrode 15, because it would then arrest the flow of material through the electrode. It is rather lifted up and occupies a position inside headpiece 11, above the upper electrode end, or is put aside.

For the substitution of a new tubular electrode section, it is necessary to close slide 27 by means of handle 28. Supply means 23, 24, 25 is disconnected from flange 26 formed on slide 27 and swiveled, for example, sideways. Following this, headpiece 11 is flanged to flange 26, slide 27 is opened and stopper l3, 13, 13 is moved from the position shown in broken lines to the position shown in unbroken lines in FIG. 1 of the accompanying drawings, where it closes passageway 14 in electrode 15. Thrust rod 12 is disconnected from stopper l3, 13, I3" and lifted up. Headpiece 11 can now be taken off as well as slide 27. After this has been done, the tubular head portion 29 is turned out of sleeve 17 and a new tubular electrode section 15 having a sleeve secured to its upper end is screwed into threaded sleeve 17. Following this, the tubular head portion 29 is screwed (in the manner shown in FIG. 1) onto the upper end of tubular electrode section 15'. The stopper reliably seals the electrode passageway against pressures of up to 1.0-atmosphere gauge. Slide 27 and headpiece 11 are brought into position, again in the manner shown in FIG. 1. Slide 27 is opened, thrust rod 12 is connected to stopper 13, 13', 13", and a new electrode shell segment is placed upon electrode 10. Stopper 13, 13', 13" is removed from its position within the electrode inside tube 15 to the position indicated by the broken lines in FIG. 1. Once slide 27 has been closed, it is possible to disconnect headpiece 11 from flange 26 and to rescrew supply means 23, 24, 25 to flange 26, and normal operation of electrode 10 can be resumed.

We claim:

1. Shutoff device for hollow electrodes supplying particulate feed material to and/or supplying gas to or removing furnace gas from electrothermal reduction furnaces, arc melting furnaces, for example calcium carbide furnaces or phosphorus furnaces or similar furnaces, comprising a supply means mounted on the hollow electrode formed with a thrust rod slidable therein, coaxially with respect to the electrode, and a stopper detachably secured to the thrust rod which can be actuated from the outside and enables the stopper to be moved inside the supply means from a position permitting the free supply and removal of material through the electrode to a position inside the electrode where the supply and removal of material therethrough is arrested, said shutoff device comprismg a stopper of SOlldmaterial having at least one corrugated steel compensator associated to it for sealing the gap left between the stopper and electrode inside wall, the compensator being arranged so as to bridge the said gap.

2. The shutoff device as claimed in claim 1, wherein the corrugated steel compensator is secured to the electrode inside wall.

3. The shutoff device as claimed in claim I, wherein the solid stopper is a metal, ceramic or glass stopper comprising a cylindrical middle portion and two conically tapered end portions.

4. The shutoff device as claimed in claim 1, wherein the individual tubular electrode sections forming the electrode inside tube are arranged so as to be spaced from one another and to be screwed together by means of a sleeve, the corrugated steel compensator being positioned in the gap left between the individual tubular electrode sections, and arranged so as to bear against a spacer shoulder formed on the sleeve, or secured thereto in different manner.

5. The shutoff device as claimed in claim 1, wherein the thrust rod and stopper are arranged so as to be connected together and disconnected by means of a bayonet joint.

6. The shutoff device as claimed in claim 1, wherein the thrust rod is arranged so as to be guided in gastight fashion by means of a packing box secured to the top of a headpiece.

7. The shutoff device as claimed in claim 1, wherein the stopper comprises three parts and clampingly receives at last one corrugated steel compensator.

8. The shutoff device as claimed in claim I, wherein the top portion of the stopper is formed with a bore receiving the threaded pin of the stopper base portion through an interposed intermediary clamp collar,

9. The shutoff device as claimed in claim 1, wherein the corrugated steel compensator is arranged to be clampingly positioned between the stopper head portion and the intermediary clamp collar and between the stopper base portion and the intermediary clamp collar.

10. The shutoff device as claimed in claim 1, wherein the corrugated steel compensator is arranged to be clampingly positioned between the stopper head portion and the intermediary clamp collar or between the stopper base portion and the intermediary clamp collar.

11. The shutoff device as claimed in claim 1, wherein the stopper base portion is formed with bores' receiving a screw spanner for screwing the threaded pin thereinto.

12. The shutoff device as claimed in claim 1, wherein the corrugated steel compensator is arranged so as to bear against a shoulder formed on the stoppers head or base portion. 

1. Shutoff device for hollow electrodes supplying particulate feed material to and/or supplying gas to or removing furnace gas from electrothermal reduction furnaces, arc melting furnaces, for example calcium carbide furnaces or phosphorus furnaces or similar furnaces, comprising a supply means mounted on the hollow electrode formed with a thrust rod slidable therein, coaxially with respect to the electrode, and a stopper detachably secured to the thrust rod which can be actuated from the outside and enables the stopper to be moved inside the supply means from a position permitting the free supply and removal of material through the electrode to a position inside the electrode where the supply and removal of material therethrough is arrested, said shutoff device comprising a stopper of solid material having at least one corrugated steel compensator associated to it for sealing the gap left between the stopper and electrode inside wall, the compensator being arranged so as to bridge the said gap.
 2. The shutoff device as claimed in claim 1, wherein the corrugated steel compensator is secured to the electrode inside wall.
 3. The shutoff device as claimed in claim 1, wherein the solid stopper is a metal, ceramic or glass stopper comprising a cylindrical middle portion and two conically tapered end portions.
 4. The shutoff device as claimed in claim 1, wherein the individual tubular electrode sections forming the electrode inside tube are arranged so as to be spaced from one another and to be screwed together by means of a sleeve, the corrugated steel compensator being positioned in the gap left between the individual tubular electrode sections, and arranged so as to bear against a spacer shoulder formed on the sleeve, or secured thereto in different manner.
 5. The shutoff device as claimed in claim 1, wherein the thrust rod and stopper are arranged so as to be connected together and disconnected by means of a bayonet joint.
 6. The shutoff device as claimed in claim 1, wherein the thrust rod is arranged so as to be guided in gastight fashion by means of a packing box secured to the top of a headpiece.
 7. The shutoff device as claimed in claim 1, wherein the stopper comprises three parts and clampingly receives at last one corrugated steel compensator.
 8. The shutoff device as claimed in claim 1, wherein the top portion of the stopper is formed with a bore receiving the threaded pin of the stopper base portion through an interposed intermediary clamp collar.
 9. The shutoff device as claimed in claim 1, wherein the corrugated steel compensator is arranged to be clampingly positioned between the stopper head portion and the intermediary clamp collar and beTween the stopper base portion and the intermediary clamp collar.
 10. The shutoff device as claimed in claim 1, wherein the corrugated steel compensator is arranged to be clampingly positioned between the stopper head portion and the intermediary clamp collar or between the stopper base portion and the intermediary clamp collar.
 11. The shutoff device as claimed in claim 1, wherein the stopper base portion is formed with bores receiving a screw spanner for screwing the threaded pin thereinto.
 12. The shutoff device as claimed in claim 1, wherein the corrugated steel compensator is arranged so as to bear against a shoulder formed on the stopper''s head or base portion. 